Skip to main content
Ch. 4 - Exponential and Logarithmic Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Non è quello che usi tu?Cambia libro di testo
Capitolo 5, Problema 144

Without using a calculator, find the exact value of log4 [log3 (log₂ 8)].

Guida verificata passo dopo passo
1
Start by evaluating the innermost logarithm: \( \log_2 8 \). Recall that \( \log_b a = c \) means \( b^c = a \). Since \( 2^3 = 8 \), we have \( \log_2 8 = 3 \).
Next, substitute this value into the next logarithm: \( \log_3 (\log_2 8) = \log_3 3 \). Using the same definition, since \( 3^1 = 3 \), it follows that \( \log_3 3 = 1 \).
Now, substitute this result into the outermost logarithm: \( \log_4 [\log_3 (\log_2 8)] = \log_4 1 \).
Recall that for any base \( b > 0 \) and \( b \neq 1 \), \( \log_b 1 = 0 \) because \( b^0 = 1 \). Therefore, \( \log_4 1 = 0 \).
Thus, the exact value of the original expression \( \log_4 [\log_3 (\log_2 8)] \) is \( 0 \).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
3m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Change of Base and Nested Logarithms

Understanding how to evaluate nested logarithms requires recognizing the order of operations and simplifying from the innermost logarithm outward. Each logarithm must be evaluated exactly before applying the next, ensuring clarity in the base and argument at each step.
Video consigliato:
5:36
Change of Base Property

Evaluating Logarithms with Simple Arguments

Logarithms with arguments that are powers of the base can be simplified using the identity log_b(b^k) = k. For example, log₂ 8 simplifies to 3 because 8 = 2^3. This simplification is key to finding exact values without a calculator.
Video consigliato:
5:14
Evaluate Logarithms

Properties of Logarithms and Exact Values

Knowing logarithm properties, such as log_b(1) = 0 and log_b(b) = 1, helps in simplifying expressions. Exact values are found by expressing numbers as powers of the base and applying these properties step-by-step to avoid approximations.
Video consigliato:
5:36
Change of Base Property